Current sources are components commonly used in metal oxide semiconductor field effect transistors (MOSFETs). These current sources can be sensitive to temperature or process variations and produce an unstable and variable output current across a range of temperatures and process variations. Typically, current sources are designed to provide a constant current across temperature or process variations using junction diodes. FIG. 1 shows a conventional current source 100 implementing a junction diode 105 to achieve band gap voltage under full complementary metal oxide semiconductor (CMOS) processes. Under CMOS processes, however, junction diodes require large areas on a circuit.
Therefore, there is a need for a constant current source that does not vary significantly with temperature or process variations that requires less area on a circuit.